Modelling unbalanced LV distribution networks using the IEC Common Information Model

Committee 57 (TC57), the core CIM specification is defined in IEC 61970-301, originally designed for Energy Management System (EMS) applications. This core is extended by IEC 61968-11 to address the specific requirements of distribution systems. Unlike transmission networks, distribution networks often exhibit unbalanced conditions, creating unique modelling challenges.

This paper focuses on the representation of unbalanced three-phase distribution networks using the IEC CIM standard. It first explores how existing CIM classes dedicated to the representation of the components for electrical conduction, consumption and power generation, as well as the connectivity between elements, can be used to model unbalanced systems in low-voltage distribution networks.

Despite these capabilities, CIM adoption in the distribution domain remains limited relative to transmission. To illustrate current practices, the paper presents two real-world case studies:

Elektro Ljubljana (Slovenia) and Unareti (Italy). These implementations highlight both the potential and the limitations of CIM for unbalanced modelling. In both cases, custom extensions and non-standard techniques were used, and unbalanced modelling was applied selectively, while many network elements remained modelled under balanced assumptions. Drawing from these examples and relevant literature, the paper critically evaluates the current limitations of CIM in supporting unbalanced modelling and discusses potential areas for standard extension to better meet distribution network needs.